ABSTRACT
This paper studies the inverse problem of determining the shape and medium parameters of a smooth seafloor from sonar data. The first section of the paper reviews beamforming techniques, the Kirchhoff (high-frequency) approximation, and a perturbation approach for a rough surface. The second section applies these ideas to the analysis of backscattered sonar signals. For a smooth surface, a stationary phase approximation is used for various measurement configurations associated with side-scan sonar and pencil-beam sonar. The rough-surface case combines the smooth-surface results with perturbation theory. These results provide an interpretation of the information content of sonar images.
